Stage set for Wallenda's daring tightrope walk over Niagara Falls

Nik Wallenda has been practicing tightrope walking for weeks but it wasn't until Tuesday that workers began installing the 1,800-foot-long wire over Niagara Falls that he plans to walk across on Friday night.

The actual time he will attempt to walk from Goat Island on the U.S. side to Table Rock in Ontario, Canada, on a high wire has been in question. The Niagara Parks Commission in Ontario, Canada, says on its website the crossing will begin at 10:20 p.m. local time. It also expects about 120,000 people to watch the spectacle that will play out about 200 feet above the falls.

"The walk should take 35-40 minutes, but if the wire feels solid and the weather is good, I might spend more time out there," Wallenda, 33, said during a media event in early May. But the seventh-generation member of the Flying Wallenda family hasn't before encountered the heavy mist and winds that may be a factor for this high-wire walk.

Other daredevils have strutted their stuff across the falls on a high wire, though not exactly over Horse Shoe Falls where Wallenda intends to cross. In 1859, Jean Francois Gravelet, a.k.a. the Great Blondin, crossed farther down the Niagara Gorge.

The event will be televised on ABC. The cost of creating and installing the steel wire and other expenses bring the price of the walk to $1.2 million to $1.3 million, according to the Associated Press.